What does bullet "grain weight" mean?

You may notice that your box of Black Sheep Ammo has a number on it, followed by the letters “GR”. What exactly does this mean, and why does it matter? Let’s discuss the importance of this label and learn why it's there.

“GR” is an abbreviation of the word “grain” or “grains” which is a unit of measurement of mass, and one grain is equivalent to 64.79 milligrams, or 1/7000th of a pound. When referring to bullets, the grain weight is only the weight of the projectile itself, not the entire bullet or gunpowder. This is an important distinction because we measure the velocity and bullet-drop of the projectile itself, so therefore we need to know the weight of the projectile to calculate accurate measurements.

The number, of course, refers to the number of grains, so if your ammo box says “124 GR” this means the weight of the projectile is 124 grains. Once again, this is only the weight of the projectile, not the weight of the gunpowder, brass, or other components of the bullet.

Let’s use the popular .223 rifle caliber as an example. The standard grain size for most .223 caliber cartridges is 55gr. This is what the military typically uses, and it provides a solid balance between velocity, penetration, and accuracy. Another popular grain choice is 62gr as it gives you a bit more punch. Because the 62gr is heavier, though, it suffers from larger bullet drop when shooting long distance. There are other grain weights for .223 such as 45gr, 77gr, and even 90gr, but these are typically used for more specific applications.

But which is better, 55gr or 62gr? To answer that question, you have to know what job you’re using the tool for. As mentioned, 62gr has slightly more energy due to its larger mass, but it falls behind when shooting long distance. Since 55gr has less mass, it has a higher muzzle velocity and doesn’t drop as much over long distances. This is why 55gr is typically favored in long distance scenarios, but 62gr tends to have deeper penetration. If you’re out hunting or doing target practice over long distances, go with the 55gr. If you use your rifle for self defense and want better knockdown power, 62gr is your choice.

There are many different grain sizes for each caliber, and each grain size has its own purpose and use case. At Black Sheep Ammo, we use tried-and-true standard grain sizes, and some of the best competition shooters in the US love our stuff.